Sex links are fertile, but in order to produce sex links certain parent stock must be used. Using a silky rooster will produce chicks, but they will very likely be dark skinned (some people don't like to eat them - others regard them as a delicacy), and egg production will be reduced in the pullets. If you are looking at a self sustainable flock, any large fowl rooster should be suitable for your needs. Understand that your sex link hens are unlikely to go broody - you will need an incubator.